<?php
/*
 *  $Id: Db2.php 7490 2010-03-29 19:53:27Z jwage $
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

/**
 * Doctrine_Connection_Db2
 *
 * @package     Doctrine
 * @subpackage  Connection
 * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @link        www.doctrine-project.org
 * @since       1.0
 * @version     $Revision: 7490 $
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 */
class Doctrine_Connection_Db2 extends Doctrine_Connection_Common
{
	/**
	 * Adds an driver-specific LIMIT clause to the query
	 *
	 * @param string $query         query to modify
	 * @param integer $limit        limit the number of rows
	 * @param integer $offset       start reading from given offset
	 * @return string               the modified query
	 */
	public function modifyLimitQuery($query, $limit = false, $offset = false, $isManip = false)
	{
		if ($limit <= 0)
		return $query;

		if ($offset == 0) {
			return $query . ' FETCH FIRST '. $limit .' ROWS ONLY';
		} else {
			$sqlPieces = explode('from', $query);
			$select = $sqlPieces[0];
			$table = $sqlPieces[1];

			$col = explode('select', $select);

			$sql = 'WITH OFFSET AS(' . $select . ', ROW_NUMBER() ' .
               'OVER(ORDER BY ' . $col[1] . ') AS doctrine_rownum FROM ' . $table . ')' .
			$select . 'FROM OFFSET WHERE doctrine_rownum BETWEEN ' . $offset .
                   'AND ' . ($offset + $limit - 1);
			return $sql;
		}
	}
}